He was convicted in 1996 of murdering his third wife, Roberta Mowery Amos. Lowell Amos was the subject of a 2006 Lifetime Network made-for-tv movie called Black Widower.
Lowell was a former General Motors plant manager. Some sources spell his first name as "Lowel".
Death of Roberta Amos
In December 1994, Lowell and Roberta Amos attended a company executive party at the Atheneum Hotel in Detroit. The Amos's went to their suite at 4:30 am. Four hours later (at 8:30 am) Lowell called Bert Crabtree, another executive from the party, and seemed to be in a panic. Crabtree and another hotel guest named Daniel Porcasi went to the room, and Lowell told them that Roberta had died in an accident.
Lowell said he needed to cleanup before calling police, and he asked Porcasi to take his sport coat for him, which he did. Porcasi, while driving home that morning looked inside the breast pocket of the coat, and found a small black leather case with a syringe without a needle, and a foul-smelling washcloth inside. Amos later reclaimed the coat, and its contents disappeared.
Amos told police that he and Roberta had engaged in sexual acts involving cocaine, and claimed she was still taking the cocaine when he fell asleep. He told police that she could not snort the drug due to a sinus problem, and that instead she took it "inside" her body. He said that when he woke up she was dead.
There was a lot of cocaine on the bed linen, including the part that was tucked under the mattress. Roberta's body contained over 15 times the lethal dose of the drug. An autopsy revealed that there was cocaine inside Roberta's vagina, but none externally. Police suspected that Amos had washed the body before calling police.
Forensic scientist Dr. Phyllis Goode found lipstick and toothmarks on a pillowcase, and other makeup residue, although Roberta did not have any makeup on her when police arrived. The bedsheets were also slightly soiled, although Roberta's body was very clean.
Investigation into previous wives', and mother's deaths
Police lacked enough hard evidence to bring charges against Lowell, so they began to follow him and look into his history. Two days after Roberta’s death, Lowell spent over one thousand dollars on dinner and drinks with two women who he proceeded to have sex with.
After the story of Roberta's death had gained publicity, several women came forward and told investigators that that they thought they had been drugged by Lowell before having sex.
Investigators found out that Lowell's first wife Saundra died under suspicious circumstances at age 36, fifteen years earlier in 1979. Saundra was found dead in her bathroom. Lowell's statement to police at that time was that Saundra had mixed wine with a sedative, collapsed, and hit her head. The cause of death was ruled indeterminate, and Amos received a $350,000 insurance payout.
Shortly after Saundra's death, Lowell married his longtime mistress, Caroline. According to friends, Lowell and Caroline argued a lot over the large insurance policies Lowell had bought on her life, and since he would not cancel the policies, she threw him out in 1988.
Lowell moved-in with his mother. His mother was rushed to the hospital just a few weeks later, seemingly stupefied. No specific diagnosis was found, and she was released. Several days later, she died.
Lowell had told Caroline over the telephone that his mother had died, when she arrived at the house Lowell was throwing his belongings into the car. He told her that he did not want people to know that he was living with his mother. Because she was 76 years old, no autopsy was performed, and authorities presumed she died of natural causes. Lowell inherited more than $1 million.
Caroline allowed Lowell to move back in with her. Nine months later she was found dead in her bathroom. Lowell's statement to police was that he’d taken her a glass of wine to the bathroom, where she was blow-drying her hair next to the full bathtub.
Later he found her dead in the bath, apparently electrocuted. No cause of death was ever determined. The wineglass that Lowell claimed to have brought Caroline was not in the bathroom, but rather found rinsed-clean and in the dishwasher. Lowell received $800,000 from the insurance policies.
Conviction
On November 8, 1996, Lowell was arrested for the murder of his third wife. Due to a 1994 change in Michigan law, the prosecution was allowed to enter details of previous incidents into the trials. Prosecutors also argued that although Lowell lacked a financial motive for killing Roberta, as he had for the other three deaths, his marriage was about to end. Roberta had already bought a house of her own, and had told friends and family that she wanted Lowell out of her life.
The prosecution surmised that Lowell killed her because he couldn’t stand rejection. They said that he first gave her a glass of wine with two crushed sedatives in it, then when she was passed-out, he injected her vagina with the cocaine (dissolved in water), and then smothered her with the pillow when she began to convulse.
On October 24, 1996, Lowell was convicted of premeditated murder and murder using a toxic substance, (both considered separate charges of first-degree murder), and was sentenced to life imprisonment without possibility of parole. He is currently in security level II at the Muskegon Correctional Facility, in Michigan. Charges have not been made in the cases of the other three deaths.